Have Node::document() return a reference instead of a pointer

Source/core/rendering/RenderRubyRun.cpp

Index: Source/core/rendering/RenderRubyRun.cpp
diff --git a/Source/core/rendering/RenderRubyRun.cpp b/Source/core/rendering/RenderRubyRun.cpp
index ac71877b1bb5372282011770360667738182e1b2..b1a89770e0029c58e026d2ad93ac68266eba5f0c 100644
--- a/Source/core/rendering/RenderRubyRun.cpp
+++ b/Source/core/rendering/RenderRubyRun.cpp
@@ -197,7 +197,7 @@ void RenderRubyRun::removeChild(RenderObject* child)
 
 RenderRubyBase* RenderRubyRun::createRubyBase() const
 {
-    RenderRubyBase* renderer = RenderRubyBase::createAnonymous(document());
+    RenderRubyBase* renderer = RenderRubyBase::createAnonymous(&document());
     RefPtr<RenderStyle> newStyle = RenderStyle::createAnonymousStyleWithDisplay(style(), BLOCK);
     newStyle->setTextAlign(CENTER); // FIXME: use WEBKIT_CENTER?
     renderer->setStyle(newStyle.release());
@@ -208,7 +208,7 @@ RenderRubyRun* RenderRubyRun::staticCreateRubyRun(const RenderObject* parentRuby
 {
     ASSERT(parentRuby && parentRuby->isRuby());
     RenderRubyRun* rr = new RenderRubyRun();
-    rr->setDocumentForAnonymous(parentRuby->document());
+    rr->setDocumentForAnonymous(&parentRuby->document());
     RefPtr<RenderStyle> newStyle = RenderStyle::createAnonymousStyleWithDisplay(parentRuby->style(), INLINE_BLOCK);
     rr->setStyle(newStyle.release());
     return rr;